title: Disruption of oral sensory relay to brain increased anxiety- and depression-like behaviours in rats.
abstract: OBJECTIVE
  Sensory information plays an important role to determine psycho-emotional behaviours of individuals. Lingual nerve can be damaged by dental surgery or trauma, such as physical irritation, radiation, chemotherapy, or viral infection. This study was conducted to examine the psycho-emotional effects of lingual nerve damage in which oral sensory relay to the brain is disrupted.
  
  
  METHODS
  Male Sprague-Dawley rats were tested for anxiety and depression-related behaviours after bilateral transections of the lingual and chorda tympani nerves (Nx) or sham operation. Tissue contents of serotonin and its metabolite in the hippocampus, hypothalamus, and nucleus accumbens were analyzed by high-performance liquid chromatography.
  
  
  RESULTS
  Sucrose preference was reduced in Nx rats compared with sham rats, suggesting the development of anhedonia, decreased pleasure seeking behaviour, by the lingual nerves transection. Ambulatory activity was decreased, anxiety-related behaviours during the activity test increased, time spent in the open arms during elevated plus maze test decreased, and immobility duration during forced swim test increased in Nx rats compared with sham rats. Serotonin level in the hippocampus of Nx rats was decreased significantly compared with sham rats.
  
  
  CONCLUSIONS
  Results suggest that aberration of oral sensory relay to brain may lead to the development of depression- and anxiety-related disorders, and decreased serotonergic neurotransmission in the hippocampus may play a role in its underlying mechanism.
authors.affiliation: Program in Craniofacial Structure and Functional Biology, Department of Dental Science, Graduate School, Seoul National University, Seoul, Republic of Korea; Department of Oral and Maxillofacial Surgery, Dental Center, School of Medicine, Chung-Ang University, Seoul, Republic of Korea.
authors.forename: Young-Jun
authors.initials: YJ
authors.lastname: Choi
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Wei-Peng
authors.initials: WP
authors.lastname: Jin
authors.forename: Yoon-Tae
authors.initials: YT
authors.lastname: Kim
authors.forename: Jeong Won
authors.initials: JW
authors.lastname: Jahng
authors.forename: Jong-Ho
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001007:Anxiety / Q000209:etiology* / Q000503:physiopathology; D001522:Behavior, Animal; D001923:Brain Chemistry; D002814:Chorda Tympani Nerve / Q000293:injuries*; D002851:Chromatography, High Pressure Liquid; D003863:Depression / Q000209:etiology* / Q000503:physiopathology; D004195:Disease Models, Animal; D006624:Hippocampus / Q000378:metabolism*; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D061222:Lingual Nerve Injuries / Q000503:physiopathology / Q000523:psychology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D013650:Taste Buds / Q000503:physiopathology*; D055697:Taste Perception / Q000502:physiology
chemical_list: D012701:Serotonin; D006897:Hydroxyindoleacetic Acid
keywords: 5-HIAA; 5-HT; 5-hydroxyindoleacetic acid; 5-hydroxytryptamine; Anhedonia; Depression; Lingual nerve; Neurotransmitter; Nx; bilateral transections of the lingual and chorda tympani nerves